Anatomy of the TR-909

01 Shift button

Even as long ago as 1983, tabletop gear was plagued by the ever-present Shift button. Then, as now, it was necessary to access a secondary level of functions below select dual-purpose buttons. You can tell which ones they are by the field of orange that surrounds some of the legending across the panel – Track and Pattern Write functions are among them.

02 Tempo Knob/Display Window

Unlike many drum machines that came before it, the TR-909 at least gave some indication of global BPM via the Display Window to its left, assuming that the various external sync functions weren’t being used. That three-digit LED display was also used to indicate the current measure, among a few